Electric heater for tanks



Sept. 7, 1948. GREEN, JR 2,448,669

ELECTRIC HEATER FOR TANKS Filed Dec. 22, 1945 2 Sheets-Sheet l Sept. 7,1948. T. F. GREEN, JR V r 2,443,569

ELECTRIC HEATER FOR TANKS Filed Dec. 22, 1945 2 Sheets-Sheet 2 l l\ k Q3 [Fara e71,/7

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Patented Sept. 7, 1948 UNITE D STAT E S PATENT OF F I CE ELECTRICHEATER; FOR TANKS ThomasF. Green, J r., OrmondQBeach, Fla.

Application December 22, 19.45,- Serial. No; 536 5816 1 Claim. 1

This invention relates to electric heating. elements for use in liquidboilers.

An object of this invention isto provide. an improved heater formountinginside aboiler, which.

is; of such constructionthat. the heating element can readily be removedin the eventany portion thereof becomes damaged.

Another object of this invention is to provide a heating unit of thiskind wherein the-resistance coils are mounted in an extruded. ceramiccore which is loosely positioned in' a closed casing so that in theevent the coil becomes broken it can be readily replaced in the ceramiccore or if the core becomes broken anew core can readily-be inserted inthe housing or cover for the unit.

A further object of this invention is to provide a unit of this kindwhich is formed with coupling or mounting meansat its outer endso thattheunit can'be mounted in various types of boilers or hot water heaters;

A further object of'this invention is to provide a heating unit of thiskind which is of such construction that. the core or the coil canreadily be replaced without draining the tank.

A further objectof this invention is to provide an improved heating unitwhich is of such construction that it can be producedat a lower costthan units of this kind at present available and at the same time willpermit ready replacement of any portion thereof.

To the foregoing objects, and others which may hereinafter more fullyappear, theinvention consistsof the. novel construction, combination andarrangement'of parts, as will be more specifically referred to andillustrated in the accompanying drawings, but it is to be understoodthat changes, variations, and modifications may be resorted to whichfall within the scope of the invention as claimed.

In the drawings:

Figure 1 is a detail side elevation of a heating unit constructedaccording to an embodiment of this invention,

Figure 2 is a longitudinal section partly broken away of the device,

Figure 3 is a sectional view taken on the line 33 of Figure 2,

Figure 4 is a detail side elevation of a unit similar to that shown inFigure 1 and 2 wherein the housing is welded to the side of the tank,

Figure 5 is an outer end elevation of the unit shown in Figure 4,

Figure 6 is a detail side elevation of another modification of thisinvention,

Figure 7 is a longitudinal section partly broken away of the unit shownin Figure 6, and

Figure 8 is an inner end elevation of the plug used with the unit shownin Figures 6 and 7.

Referring to the drawings and first to Figures 1, 2 and 3, the numeral10 designates generally 21 an elongated tubular'housing which isprovided witha: closed inner end. I I. The'outer end of the housing H1is open and a mounting plate I2 is welded; brazed or otherwise firmlysecured, to the l housing H! at a point, inwardly from the outer endthereof, asindicated at 13, and the plate I2 is adapted to be securedtothe side wall Id of a boiler by fastening members [5. Preferably asealing, gasket IB'is interposedbetween the plate t2: and the side wall.M of the boiler. The housing Ill'hasloosely mounted therein an elongatedceramic core IT.

The corel'l is formed with a plurality of longitudinally extendingboresI8 positioned about the center thereof and is also formed with a centralbore I 9. There is an electric resistance coil 20 in each, of the bores|81 and in practice the coils of the resistance member 20 are formedintegral with each" other, sothat a single length of resistancewiremaybeused which is extended through the bores t8; and then bent about theends of the core I! in order that onlytwo ends 2| and 22 will: beprovided for connection with a pair of terminalposts, 23 and 24respectively.

An outer plug; or cap 25. which may be formed oft ceramicmaterialengages within the outer end of; the housing. Ill being removablysecured thereinby'means of a; bolt 26- extending diametrically through.the outer. end of the housing and of the plug; 25:. The plug;25zisformed at its inner side with: an annular chamber 21 within whichthe ends: of the resistance Wires are adapted to engage whereby thewires may be readily connected to the terminal members 23 and 24. Aninner cap 28;.whi-ch-mayalso:beformed of ceramic material, also engagesoverthe inner end of the core I! being formed with an annular chamber 29whereby the inner ends of the coils of the resistance wire 20 may beextended from one bore 18 to an adjacent bore. A securing bolt 30extends through the central bore [9 having an inner head 3! which iscounter-sunk in the inner cap 28 and the outer end of the bolt 30 isthreaded into the center of the plug 25. In the formation of the core I!this core is preferably formed by extruding the ceramic material, so asto provide a round core which is also formed with the circumferentiallyspaced apart bores or openings for the resistance coils and it is alsoformed with a central bore for receiving the clamping bolt 30.

Referring now to Figure 4, there is disclosed a heating unit which issimilar in every respect to the heating unit shown in Figure l, with theexception that the mounting plate I2 is eliminated and the housing illis secured in the side wall M of the boiler by means of brazing orwelding as indicated at 32. In other respects the heating unit Ina shownin Figure 4 is similar to the construction shown in Figures 1, 2 and 3.

Referring now to Figures 6, 7 and 8, there is disclosed a heating unitwhich embodies a construction that may be threaded into the side wall ofa boiler where the wall is heavy enough to form threads or where areinforcing bushing is secured to the side wall for receiving a heatingunit of this type. The heating unit shown in Figures 6, 7 and 8 includesa tubular housing 33, which is closed by a curved wall 34 at its innerend and is open at its outer end. The tubular member 33 is tightlysecured within the inner end of an externally threaded nipple 35 whichis formed with a nut head 36. A ceramic core 31 formed withcircumferentially spaced apart bores 38 for receiving resistance coils39 is disposed within the tubular member 33 and extends through thenipple 35. The nut head 36 is provided with an annular chamber 49 withinwhich a ceramic plug M is adapted to be positioned. The plug 4| isremovably secured in the counterb-ore 40 by means of a set screw 42. Theplug 4| has extending therethrough a pair of terminal members 43 and 43- which are adapted tobe connected to the two ends of the heatresistance coils 39. The plug il at its inner end is formed with anannular chamber 45 within which the inner ends 36 and 4'! of theterminal members 43 and M are adapted to engage so that the outer endsof the heat resistance coils 39 may be left relatively long in orderthat the plug All may be partially withdrawn from the head 36 withoutpulling out the core 31.

In the use of this heating unit where the tank is of such constructionthat the housing for the unit can be welded to the side wall of thetank, the construction shown in Figure 4 is used or if the tank wall isrelatively thick, the construction shown in Figures 1, 2 and 3 may beused. Where a bushing is provided in the side wall of the tank havininterior threads, the construction shown in Figures 6, '7 and 8 is used.In the event any portion of the heating unit becomes broken or damagedthe core including the heat resistance coils may be removed as a unitwithout removing the housing which is sealed with respect to the boiler.Where the construction shown in Figures 1, 2 and 3 is used, the core maybe removed by withdrawing the locking bolt 26. The core can then bepulled out of the sealed housing In and any portion of the unitincluding the ceramic core or the heat resistance coil can be replaced.Through the provision of an extruded ceramic core the manufacturing costof the heating unit 4 is very considerably reduced and by providing theheat resistance coil, which is loosely mounted within the bores of theceramic core, the resistance coil can easily be replaced without damageto the ceramic core. It will be apparent from the foregoing that thisunit can be easily and quickly and cheaply repaired or replaced and thatonce the housing has been tightly secured to the side -wall of the tankthe housing need not be removed or disturbed in the event any portion ofthe unit becomes unserviceable.

The heater shown in Figures 6, 7 and 8 may be used in either boilers ortanks, or in pipes and pipe fittings such as are used in instantaneoustypes of heaters.

The exact configuration illustrated is regarded as the optimum, but someof the desirable results inherent in this disclosure may be obtained byvarious slight modifications including some departure from the exactconfiguraton shown, and it is therefore requested that the scope of theinvention should be regarded as limited only by the terms of the claim.

What I claim is:

A tank heater comprising a tubular housing for extension into a tank, aclosed inner end on said housing, a ceramic core loosely disposed insaid housing and formed with a plurality of circumferentially spacedapart bores, a resistance coil loosely disposed in said bores, a plug inthe outer end of said housing, said plug formed with an annular recesson the inner end thereof adj acent the outer end of said core, a pair ofterminals carried by said plug extending therethrough and into saidrecess and connected to said coil, and means removably securing saidplug in said housing.

' THOMAS F. GREEN, JR.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date Re. 17,093 Torriani Oct. 2, 19281,394,518 Abbott Oct. 25, 1921 1,670,437 Campbell May 22, 1928 1,688,796Baker Oct. 23, 1928 1,715,287 Head May 28, 1929 2,069,348 Young Feb. 2,1937

